The invention relates to a door closer.
Door closers are known which have closing springs as energy accumulators and hydraulically damped closing motion, in which the closing spring cooperates with a hydraulic piston-and-cylinder unit. The piston-and-cylinder unit and the closing springs are disposed in a housing and act through a rack and a pinion or through cam drives with a closing shaft journaled in the housing, which is connected directly or through a force-transmitting linkage to the door. When the door is opened manually the energy accumulator is charged and then discharged by the automatic closing of the door. In each opening and closing of the door the operation of the piston exchanges hydraulic fluid between the two piston working chambers. A manual door closer constructed in this manner is disclosed, for example, in DE 36 38 353 A1.
In closers of this kind, scissors rods or sliding arm rods are used in practice as the force-transmitting linkages. There are closers which are mounted on the door leaf or on the frame.
The use of such known hydraulic door closers on fire doors is not free of problems on account of the flammability of the hydraulic fluid. Heretofore it has been necessary to assure that a closer mounted on the side of a door that faces away from the fire does not become leaky even when greatly heated by a fire. Leaking hydraulic oil would catch fire directly on a hot door and threaten further propagation of the fire. On account of such stringent requirements regarding leakage the manufacture of the door closers is relatively complex. Also, the use of low-melting materials such as plastic in the door closer housing has been prohibited.
In DE 195 15 169 A1 it is proposed to use fusible fasteners in the form of fusible plastic screws for mounting door closers on the side of fire doors facing away from the fire if a fire occurs, so that in case of fire the fastener will melt and the door closer will fall from the door. This means, therefore, that the door closer will fall from the door before the door closer housing becomes hot on the hot door in case of fire. If the door closer should remain on the hot door, the result could be that the door closer housing fastened to the door might burst and the oil in the housing might run out and/or start to burn and/or burn on the door.
The invention is addressed to the problem of developing a door closer which can be used also on fire doors and which can be installed easily and securely.
This problem is solved according to the invention by a door actuating system for the door of a fire doorway, comprising (1) a driver housing; (2) at least one of (a) a motor driving device with an outside energy source disposed in the driver housing for opening and closing the door or (b) a restoring device disposed in the driver housing that is energized when the door is opened and is designed as an energy accumulator for the automatic closing of the door; (3) a damping device disposed in the driver housing for damping at least one of a closing or an opening movement of the door; (4) an output means journaled in the driver housing and cooperating with at least one of the motor driving device, the restoring device, or the damping device; and (5) a force-transmitting linkage connected to the output means and supported in a rotary bearing or a slide bearing. The rotary bearing or the slide bearing is fastened to the door or to a fixed door frame through a fastener. The driver housing is fastened to the fixed door frame and to the door through a mounting device. The mounting device has on the door and door frame a heat-conducting fastener that melts at temperatures greater than 500xc2x0 C. The heat-conducting fastener is disposed in an area of a fusible safety device, which in case of fire melts and releases the fastening of the driver housing on the door and on the door frame. The driver housing may have a separate mounting plate or one formed in one piece with the housing that comprises a plastic material.
The release of the fastening prevents the door closer or an inflammable medium in the door closer from catching fire on the hot door on the side of the door facing away from the fire. Inflammable mediums may be contained, for example, in gearing, couplings and damping devices.
This inflammable medium may be a hydraulic oil or a hydraulic damping device, a hydraulic drive or a hydraulic coupling, as well as other inflammable media suitable for use in such devices.
The use of the highly heat-conducting fastener assures that, in case of fire, the fusible device will melt if the heat is sufficient, and that the door closer housing can come loosexe2x80x94fall, for examplexe2x80x94automatically from the door or door frame. Preferably plastic is used in making the fusible device. However, a low-melting metal can also be used, e.g., one melting at less than 300xc2x0 C.
The fastener, which is made of material of high thermal conductivity and not melting or melting only at a high temperature greater than 300xc2x0 C., especially greater than 500xc2x0 C., can be made of metal, especially copper or steel.
The high thermal conductivity of the fastener assures that, in case of fire, the transfer of heat from the hot door to the fusible device will be high, i.e., much heat is transferred to melt the fusible device quickly and surely.
At room temperature the fusible device provides a force-transmitting connection between the closer housing and the door and the door frame. At temperatures above 300xc2x0 C. the plastic starts to melt. The fastening of the closer housing thus also is released. The desired melting temperature can be selected by choosing the appropriate plastic or by varying its composition in the appropriate manner.
It is especially advantageous in this connection if the closer housing and/or a mounting plate of the closer housing is made from weakly heat-conductive material, e.g., of plastic, asbestos or substitutes, ceramic, glass or materials compounded of these substances, in order to assure that the medium in the closer housing, oil for example, is slowly and not greatly heated. Thus any heating of the oil and bursting of the closer housing is at least delayed, and preferably prevented, as long as the closer housing is mounted on the door when hot in the case of fire.
Also the fastening device of the sliding or rotating joint in which the force-transmitting linkage is supported on the door or door frame should advantageously release in case of fire. This is accomplished, for example, by the automatic unhooking of the connection to the closer housing as soon as the latter is released from the door or door frame, or preferably by the sliding or rotating joint""s own fusible device. In case of fire, the drive housing and linkage will thus drop together and early to the floor before the door closer or its housing and the oil becomes hot. Without the direct contact to the door surface there is no longer any danger that hydraulic oil will catch fire.
In a first embodiment, the mounting screws of the mounting device with which the closer housing and the sliding or rotating joint is mounted on the door or door frame is made of metal.
In a modified embodiment, the fusible device has collars of plastic which are held in mounting bores of the closer housing or of the rotary or sliding bearing.
The outside diameter of the collars is greater than the diameter of the head of the mounting screw, so that the bores in the closer housing or in the rotary or sliding bearing let the screw heads pass through them as soon as the collars melt in case of fire.
In an additional embodiment, the closer housing or rotary or sliding bearings are fastened on mounting plates of a good thermal insulating material or low-melting material, e.g., plastic. The mounting plates are fastened in turn on the door or door frame. The closer housing mounting screws, consisting of material of good thermal conduction enter only into the mounting plate, but not into the door frame or door. In case of fire, when the mounting plates melt in the area of the screws of good thermal conduction, the closer housing and rotary or sliding bearings lose their hold and fall to the floor.
Alternatively, the closer housing and/or the force-transmitting linkage and/or the rotary or sliding bearing can be made in whole or in part of highly thermal insulating and/or low-melting material, such as plastic. In this case other thermal insulating and/or low-melting mounting plates or the like can be dispensed with. Through the use of plastic for housing and linkage a good thermal insulation from the door made hot by the fire is achieved, so that the heating of the medium in the closer housing takes place but very slowly.
The housing of the closer can consist of thermal insulating material, but also of metal, especially if a mounting plate of thermal insulating material is used.